[mythtv] More scheduling scheduler

Bruce Markey bjm at lvcm.com
Fri May 5 19:57:08 UTC 2006

Jack Perveiler wrote:
> By "SchedMoveHigher" are you referring to the setting enabled by the
> "Rescheduler Higher Priorities" checkbox in the Recording Priorities menu
> (sorry, I'm not up on the scheduler lingo)?  If so then I intentionally leave
> it off.  

"SchedMoveHigher" is the name of the function and is also referred
to by the TLA SMH. Other lingo, TUQ or BUQ is The Ugly Query or Big
Ugly Query which is the core of the scheduler.

> I have 1 hidef card (with a higher priority) and 2 std def cards.  With that
> option set I got bit at the beginning of the season.  The networks would
> advertise reruns for first run season premiers the next week, but would change
> them frequently depending (presumably) on ratings.  Instead of capturing a show
> that night on a std def card it instead opted to wait for next week when it
> could get it on a special night in hidef.  Then the rerun would be cancelled in
> favor of a rerun for a different show and I'd be left high and dry.

This is the warning that David put in the help text and I mentioned
in the HOWTO. This is rare but it can happen.

> Also, there's the water cooler effect.  Some shows just can't be put off or
> I'll end up the social leper at work :)  I wait until they've recorded for a
> while so I can skip commercials, but I definitely watch it before the next
> morning.  

No doubt that you want to leave this off if you are concerned about
this. This is one of the reasons that "L"ater is shown in white and
included in the Important view. While the scheduler may find that
things would work out better if this showing was postponed, you need
to know that you could record this showing by clicking "Record anyway".
As slick as the scheduler may be, it can not read minds and ultimately
you are the only one that can decide what you really want in a
specific situation.

> Instead of obsoleting that option, would you consider maybe just changing the
> default to "on"?

Agreed, I've always believed this option should exist but the
default should be "on".

One of the reasons I think SMH should be on is that it is easier
to override when a show is Latered for you than to figure out the
postponement for yourself if it is not. In the case of a conflict,
it may not be obvious that one of the shows could be latered. Which
title and which of the rebroadcasts would work out best as far as
the effect on other overlapping shows may be a matter of trial and
error. I think it's better to have the scheduler figure out a good
solution for you then if you want override the Later, you just need
to click one button.

More importantly, while there is roughly a less than 1% change that
the rebroadcast(s) may disappear, there is a greater than 99% chance
that the lower priority show marked as a conflict would never record
(the listings may change and add a rebroadcast).

All this is true in the general case even though...

> First, let me say I think I misspoke slightly.  My hidef card doesn't have a
> higher priority specified by me someplace... I made my hidef CHANNELS a higher

...it doesn't apply to this specific case as this was not the result
of SMH. Here the episodes was favored on the favored channel.

> priority.  I couldn't see where cards can be given higher priority except via
> their card number.

That's not quite right. Priority can be added per input and not per
card. If one card has two inputs, the input preference in mythtv-setup
could be set differently for each input but there is no priority setting
for the card number.

The scheduler used to place the highest priority show on the lowest
numbered input where a showing of the episode was available. Therefore,
the order in which you add your cards and inputs is important. You can
over come the input order with input preference or channel priority
but this has another effect.

Say there are two cards with one input each for the same source. Show
"A" is on a 7pm and is high priority. Show "B" is lower priority and
is shown at 7pm and 10pm. If the inputs are equal, "A" records on card
1 at 7 and "B" records on card 2 at 7. If input preference was added
to input 1 (or input 2) it would say that it is better to record on that
input whenever possible. "A" would still record on card 1 at 7 but "B"
would record on card 1 at 10pm when the better input is available.

> That being said, if I follow your suggestion and remove the extra priority on
> the hidef channels will things be any different?  Is card priority (determined
> by it's card number) handled differently by the scheduler than channel
> priority? 

Because you had two different sources with channels that carry the
same station, channel priority had the same effect of using the better
channel when it was available.

Therefore, if your hidef input was first and had the same priority
as the two std def cards and there where two hidef shows on a common
station at the same time, the lower priority show would record the
earliest showing on one of the std def cards.

If on the other hand, the std def cards have lower numbered inputids,
having the same channel and input priorities will cause it to always
prefer std def.

> Along a different tack, wouldn't a conflict also cause this problem?  If I have
> 3 tuners and 4 shows wanting to be scheduled, and the scheduler sees it could
> grab a high priority show next week, I think I would still get bitten by a
> schedule change.  I'd much rather have the low-priority "Everybody Loves
> Raymond" rerun dropped than the CSI season premier missed due to a later
> schedule change.

3 tuners and 4 shows can cause a Later but it is the lowest priority
show that would be postponed if it has a rebroadcast. This is the
defining characteristic of SMH; if it is off, higher priority shows
will not be moved for the sake of lower priority Conflicts.

Back to your example of hidef channel priority. If CSI was your one
and only rule, an analog channel had an episode on Thursday that was
repeated on the hidef channel on Friday, it would be scheduled for
hidef on Friday if that channel had a higher priority. You've told
it to use the better channel whenever possible and no other conflicts
need to be involved for it to make this decision.

There are several reasons that a show can be Latered besides SMH.
Low priority show would be a conflict but has a later showing (most
obvious =), a later showing may have an override to specifically
record that showing, a preferred search rule matches a later showing,
a rule with more specific type (say, weekslot) for the same title is
a match for a later showing.

> Granted schedules don't change THAT often, but the time they seemed to change
> the most was also the time I least wanted to miss something (premier weeks). 
> Between that and the water cooler effect I guess I'm still lobbying for
> SchedMoveHigher to remain an option :)

Granted it should remain an option that can be turned off, however,
on or off would have no effect in your case of channel priority or
any of the other causes of Latered showings mentioned. Now, if you
are talking about series premiers, the Custom Record "First Episodes"
would have worked for you as this only matches showings on the first
day that they are broadcast. Search for "First Episodes" in the
archives or see http://www.mythtv.org/docs/mythtv-HOWTO-12.html#ss12.5
and check out the "First Episodes" example.

Finally, a side note that I can't help wondering about; if you
missed the premier of a show that was canceled a few days later,
did you really miss anything? Perhaps you saved an hour of your life
(or maybe 5 or 10 minutes before you hit Delete then removed the rule
for the new show ;-).

--  bjm

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